Tropical Fish Site

Profiles Reviews Guides for Tropical and Marine

Flagtail – Semaprochilodus Insignis


Common name: Flagtail

Scientific name: Semaprochilodus Insignis

Average Adult Fish Size: 14 inches / 35 cm

Place of Origin: Ecuador, Peru, Colombia, Guyana and Brazil

Typical Tank setup: Amazon riverine biotope with driftwood/bogwood and rocks. They will eat any soft leaved plants and attempt to eat even hard leaved plants, so plants are probably out of the question. Flagtails are very good algae eaters so adequate lighting is helpful to promote its growth.

Recommended Minimum Aquarium Capacity: Juveniles up to 4 inches /  7.5 cm can be housed in a a 40 gallon / 160 litre but full grown adults will need a 100 gallon / 400 litre or larger aquarium.

Compatibility: It’s aggressive towards its own kind when kept in small numbers, but can be maintained in groups of six or more in larger tanks. Otherwise it’s best kept as a single specimen in a community of medium to large fish. Suitable tankmates include other large characins, Loricariids, Doradids, peaceful cichlids, knifefish, arowana and freshwater stingrays.

Temperature: 73 – 84 Deg F /  23 –  29 Deg C

Water chemistry: pH: 5.5 – 7.2

Feeding: Though omnivorous it’s primarily a herbivore. Offer plenty of vegetable matter in the form of blanched spinach, lettuce, cucumber, algae wafers and similar. It will also accept most good quality dried foods and small frozen fare such as bloodworms, brine shrimp, or daphnia.

Sexing: Difficult to sex, although mature females are said to be rounder-bellied than males.

Breeding: They are known to be egg scatterers, and migrate long distances in the wild to spawn. Due to their large adult size it is unlikely that they will spawn in an aquarium.

Additional Information: Flagtails are excellent jumpers, so a tight fitting lid is a must.